The 4 Cs: Color, Cut, Clarity, and Carat.

The "4 Cs" of diamond buying are often misrepresented so we're going to simplify them as much as possible for you.

This is one of the things you really have to understand when you're out shopping, because if you don't you're bound to get run over by salespeople who are anxious to close a sale.

Color.

The best diamonds are colorless. Diamond color is graded by professionals certified by various gem certification organizations (The GIA and IGI are two that you'll hear mentioned frequently) on a scale that goes from D to Z. Grading is done by eye with the stone loose on a bright white background. This is how you should look at the diamond, even if it's set: on a white piece of paper.

Grades D-F are considered colorless.Grades G-J are considered near-colorless.Grades K-M are called faint yellow.Grades N-R are very light yellow.Grades S-Z are light yellow.

Most stones in the D-G range are going to look almost identical to an untrained eye. At around H, you may start to see what professionals call "warmth" in the stone: you'll see a very slight tint. After H, that tint becomes much more pronounced. The yellows here aren't exactly a desirable shade: the diamonds often just look dirty. For a white diamond, you'll probably want to stay in the D-I range. An H or an I color diamond won't look too different from a D, but it could be a lot less expensive.

Clarity.

Clarity refers to the external and internal visual characteristics of a diamond, called blemishes and inclusions. Clarity is graded under 10-power (10x) magnification, though some clarity characteristics in the lower grades can be seen with the naked eye. These irregularities can include tiny crystals or bubbles, fissures, or other imperfections. Here are the grades:

FL — IF: Flawless — Internally Flawless. The rarest stones have no inclusions or blemishes visible to a trained eye with 10x magnification. These are exceptionally expensive.

VVS1 — VVS2: Very, Very Slightly Included. Inclusions that are very difficult to see by a trained grader under magnification.

VS1 — VS2: Very Slightly Included. Inclusions difficult to see under magnification, minor but visible when magnified.

SI1 - SI2: Inclusions visible under 10x magnification.

I1- 13: Included. Usually visible to the naked eye. Diamond appearance affected. I

A VS2 diamond or higher will not have inclusions you can see unless you plan on looking at your diamond with a microscope or jeweler's loupe. The lower grades may be cheaper, but the inclusions may not make for the prettiest stone.

Much of that, however, is dependent on the next C...

Cut.

Of the 4 Cs, cut is probably the most important: the cut of the diamond

is what gives the stone its scintillation and fire, which is what ultimately makes it sparkle and explode with prismatic color. Even a stone with relatively mediocre color and clarity can be brought to life by a cutter who knows what he's doing.

In a well-cut diamond, light enters the top (the "crown" and the "table") and exits the top, like it's absorbing light and spitting it back out in fireworks. In diamonds that are cut too shallow or too deep, the light bleeds out the bottom and sides of the diamond, making it look smaller, darker, and altogether lifeless.

While there are ideal mathematical proportions that describe the angles and percentages needed to make an ideal cut diamond, what you're interested in is the grading certification on the cut: look for Ideal, Excellent, and Very Good. More so than that, let your eyes be the judge. Does the diamond sparkle more or less than the others in the case? Does it look dark when you look down into it?

Carat.

Carat weight may be the most widely misunderstood component of diamond buying. Carat is a unit of weight measurement. One carat is equal to one-fifth of a gram (.20g).

What carat does not determine is fire or scintillation. It only determines size and weight. Size and weight do, however, play a role in the fifth "C" of diamond-buying... Cost.

This is important for a couple of a reasons. A man (or woman) who goes out with a budget could very easily come home with the biggest possible diamond for the price. However, if you're just buying for carats, you're going to get a much less attractive stone than if you had bought the best cut, color, and clarity in your price range. A small, well-cut diamond with very good color and clarity will always look better than a larger stone with mediocre color, cut, and clarity.